Long-stroke pumping unit

A pumping unit to reciprocate a rod string for a downhole pump disposed in a well, the pumping unit comprising:

• a tower;
• a counterweight assembly being movable along the tower;
• a belt disposed on the tower and being connected between the counterweight assembly and the rod string;
• a prime mover configured to reciprocate the belt on the tower;
• a plurality of sensors configured to measure a plurality of sensor measurements, the senor measurements at least including a first position associated with the rod string, a measured force exerted on the rod string, and a measured vibration associated with the reciprocation of the rod string in the well;
• and
• a controller connected to the prime mover and the sensors, the controller being configured to:
• monitor for failure of at least one of the rod string and the belt based on at least one of the sensor measurements;
• and
• control descent of the counterweight assembly along the tower in response to detection of the failure.